The definition of productive reservoirs by the method of fuzzy inference

The lithological classification and allocation of reservoirs are based on the difference of physical and geophysical parameters of rocks. Finding the values of physical and geophysical parameters in some ranges makes it possible to predict the lithology of the formation. The class of information systems based on fuzzy logic provides an effective use of existing knowledge about a certain object. This allows to apply fuzzy logic in intelligent systems of interpretation of well geophysical research materials

Crystal structure of mixed fluorites Ca(1-x)Sr(x)F(2) and Sr(1-x)Ba(x)F(2) and luminescence of Eu(2+) in the crystals

Within the framework of the virtual crystal method implemented in the shell model and pair potential approximation the crystal structure of mixed fluorites Ca(1-x)Sr(x)F(2) and Sr(1-x)Ba(x)F(2) has been calculated. The impurity center Eu(2+) and the distance Eu(2+)-F in this crystals have been also calculated. The low level position of excited 4f65d configuration of the Eu(2+) ion has been expressed using phenomenological dependence on distance E(2+)-F. The dependences of Stokes shift and Huang-Rhys factor on concentration x have been received for yellow luminescence in Sr(1-x)Ba(x)F(2):Eu(2+). The value x, for which the eg -level of Eu(2+) ion will be in conduction band in Sr(1-x)Ba(x)F(2):Eu(2+) has been calculated.Comment: 8 pages, 3 figures. The manuscript is sent to journal 'Physics of the solid state'. The results will be submitted on inernational conference SCINTMAT'2002 in oral session (june,20-22,2002,Ekaterinburg,Russia). Corresponding author e-mail: [email protected]

Lifetime of Gapped Excitations in a Collinear Quantum Antiferromagnet

We demonstrate that local modulations of magnetic couplings have a profound effect on the temperature dependence of the relaxation rate of optical magnons in a wide class of antiferromagnets in which gapped excitations coexist with acoustic spin waves. In a two-dimensional collinear antiferromagnet with an easy-plane anisotropy, the disorder-induced relaxation rate of the gapped mode, Gamma_imp=Gamma_0+A(TlnT)^2, greatly exceeds the magnon-magnon damping, Gamma_m-m=BT^5, negligible at low temperatures. We measure the lifetime of gapped magnons in a prototype XY antiferromagnet BaNi2(PO4)2 using a high-resolution neutron-resonance spin-echo technique and find experimental data in close accord with the theoretical prediction. Similarly strong effects of disorder in the three-dimensional case and in noncollinear antiferromagnets are discussed.Comment: 4.5 pages + 2.5 pages supplementary material, published versio

Hole-hole superconducting pairing in the t-J model induced by spin-wave exchange

We study numerically the hole pairing induced by spin-wave exchange. The contact hole-hole interaction is taken into account as well. It is assumed that antiferromagnetic order is preserved at all scales relevant to pairing. The strongest pairing is obtained for the d-wave symmetry of the gap. Dependence of the value of the gap on hole concentration and temperature is presented. For the critical temperature we obtain Tc about 100 K at the hole concentration delta = 0.2-0.3.Comment: replaced with a revised version to appear in PRB, 6 pages, REVTeX 3.0, figures not change

Bis{4′-[(2,3,5,6,8,9,11,12-octa­hydro-1,4,7,10,13-benzopenta­oxacyclo­penta­decin-15-yl)meth­oxy]-2,2′:6′,2′′-terpyridine}cadmium(II) bis­(hexa­fluorido­phosphate) trihydrate: a powder study

The asymmetric unit of the title compound, [Cd(C30H31N3O6)2](PF6)2·3H2O, contains one half-cation with the CdII center situated on a twofold rotational axis, one hexa­fluoridophosphate anion and two uncoordinated water mol­ecules, one of which is also situated on a twofold rotational axis. The cations are associated into columns along the a axis through π–π inter­actions between the pyridine and benzene rings, with a centroid–centroid distance of 3.72 (5) Å. Inter­molecular O—H⋯O, C—H⋯O and C—H⋯F hydrogen bonds consolidate the crystal packing

SYNTHESIS OF TANTAL POWDERS BY SECONDARY REDUCTION IN KCL–NACL MELTS

The work was carried out with the financial support of the UrB RAS Program 2015-2017. "Materials and technologies for nuclear, alternative and renewable energy" (Project No. 15-20-3-20)